Let me anticipate the inevitable “why don’t you just use Google Maps” question: to the best of my understanding, tracing your airport vectors off of Google Maps imagery is an unlicensed use of their service and would result in a derived product owned by Google. That’s pretty much a deal breaker.
OSM’s use of background imagery to trace (in Potlatch) comes from specific license agreements between OSM and the image provider – in other words, the image providers are “donating” to OSM by giving them a specific license to trace without ownership issues.
Anyway, I am open to other ideas. (Except for “no, you didn’t read the license right, Google really doesn’t mind if you use their imagery for free to create your own data set”. I am not open to that! 🙂